﻿//  Copyright 2020 Google Inc. All Rights Reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.

using NtCoreLib.Utilities.Memory;
using System;
using System.Runtime.InteropServices;

namespace NtCoreLib.Win32.Security.Interop;

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
internal sealed class SecBufferDesc : IDisposable
{
    const int SECBUFFER_VERSION = 0;

    public int ulVersion;
    public int cBuffers;
    public IntPtr pBuffers;

    void IDisposable.Dispose()
    {
        if (pBuffers != IntPtr.Zero)
        {
            Marshal.FreeHGlobal(pBuffers);
        }
    }

    public SecBufferDesc(SecBuffer buffer) : this(new SecBuffer[] { buffer })
    {
    }

    public SecBufferDesc(SecBuffer[] buffers)
    {
        int size = Marshal.SizeOf(typeof(SecBuffer));
        ulVersion = SECBUFFER_VERSION;
        cBuffers = buffers.Length;
        pBuffers = Marshal.AllocHGlobal(buffers.Length * size);
        int offset = 0;
        foreach (var buffer in buffers)
        {
            Marshal.StructureToPtr(buffer, pBuffers + offset, false);
            offset += size;
        }
    }

    public SecBuffer[] ToArray()
    {
        return pBuffers.ReadArray<SecBuffer>(cBuffers);
    }
}
